Hey,
Yes you can definitely exceed 74 overall, especially if you are talking about a defenceman ( i have already seen 80+ for a forward as well). First of all, your total possible overall depends on the player type, for example, sniper vs playmaker, defensive defenceman vs offensive defenceman vs two-way, etc, all have different total possible maximums. Second of all, boosts matter a lot. To reach your maximums you need to unlock your boost slots and ideally all of your +7 boosts, whether earned or bought.
I have my Legend 1 card and my defensive defenceman build is 88 Overall, 86 Overall for my two-way build. I'm using my boosts. With legend 3 i should be able to break 90 Overall. However, having the maximum possible overall is not always the best. Build your player to match your playing style. I sacrafice some max Overall in order to stack boosts for speed (a +7 and a +5), etc, which is more important to my style of play.
By FAR, the most important attributes for increasing your Overall rating is Offensive Awareness and Defensive Awareness, as they are modifiers which affect many other attributes. Adding 10 points in either can literally increase your Overall rating by several points.
To answer your other question about attributes:
Deking: Self explanatory
Hand-Eye: This increases the likelihood that your player will do a bat in goal, or bat down, also attempt deflections and helps with receiving hard passes Also this helps with being able to connect with one timers and the accuracy of those shots.
Off. Awareness: Offensive skills Modifier. And for picking up loose pucks.
Passing: This affects the teammates pass reception, so they can receive the pass better. If you want to increase your own pass reception then increase Hand eye. Also affects passing accuracy. At high levels it allows you to pass through more traffic without your pass being intercepted.
Puck Control: How easy/difficult it is to get the puck away from you after a poke/sticklift/hit
Slap Shot Accuracy: Self explanatory
Slap Shot Power: Self explanatory
Wrist Shot Accuracy: Self explanatory
Wrist Shot Power: Self explanatory
Aggressiveness: Affects intimidation. Body Checking modifier.
Body Checking: Self explanatory
Def. Awareness: Modifier for defensive skills + Increases the likelihood of intercepting passes, so to stop cross crease passes you need to be in the passing lane but also have good defensive awareness, picking up loose pucks in the defensive zone. At high levels your player will have automatic defensive skills.
Discipline: Self explanatory. Helps avoid 5 minute majors the most. Especially those 5min + 10min game misconducts for hitting from behind.
Faceoffs: Self explanatory
Fighting Skill: How good you are in fights.
Shot Blocking: Affects which kind of block you will do, and how fast you get up after blocking.
Stick Checking: Poke checking and stick lifting. Avoiding tripping calls.
Acceleration: Self explanatory
Balance: Affects skaing radius, throwing and receiving hits (stay on your fee)t. Also while in puck protect you will be less likely to lose an edge and fall.
Durability: Avoid injuries
Endurance: Self explanatory, does not affect Overall rating much but very important for maintaining speed in the second half of periods.
Speed: Top speed
Strength: Affects being able to pin a guy to the boards, or escape boardplay. Modifier on shot power, hitting power, and punching power in fights
